You really need to think about an alternative method to healing than dog form if you want to kill high end monsters. The problem is that a single hit from a balron can do a third to a half of your hit points, and multiple hits can come right after each other. No amount of hit point regeneration can counter such damage.
I have a friend who runs with a bracelet of health (+10HPR) and Voice of the Fallen King (+5 HPR) in addition to dog form, and he still needs good cross healing against the big things. Anything smaller, he destroys.
So you really need to add healing/anatomy or bushido or 60 chivalry in order to be effective.
The second thing you should think about is with a fast fencing weapon, you don't need a lot of swing speed in order to be effective. You could easily replace your assassin suit (save it for a mace fighter or swordsman who has slower weapons) with something with more LMC/resist/HPR.
And the third thing you should keep in mind is raising your fencing as high as possible.
Without bushido, parry isn't doing you much good with the spear. Think about adding bushido, dropping parry or getting a shield.
The good things:
With 100 ninja and mirror image, you have a 70% chance of not getting hit at all. Add parry and a shield to that or parry and bushido, and you will only take damage very rarely.
Smoke bombs mean getting out of trouble quickly.